Process of cracking oil



A ril 19, 1932. EGLOFF 1,854,464

PROCESS OF CRACKING OIL I Original Filed Dec. 25, 1925 Patented Apr, .119, i932 llhllilhfi STATEd raranr error GUSTAV EGIJQEF, E CHICAGO, ILLINOIS, ASSIGNOR T0 UNIVERSAL 0E PRODUGTS (JUMP-ANY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA IEEQOESS OI CRACKING OIL Application filed December 23, 1925, Serial No. 77,187. Renewed may 6,, 1929.

This invention relates to improvements in process of cracking oil, and refers more particularly to that type of process in which the oil is passed through a heating coil and thence to an expansion chamber, and the vapors removed therefrom, then to a reflux condenser where the heavier portions are condensed and returned to the system for further treatment. In certain cases in which m such a process is operated, dificulty is experienced in stripping the reflux condensate of the gasoline with the result that a certain portion of the gasoline passes out with the reflux condensate and is again recracked. It 315 is, of course, obviousl undesirable to recrack the gasoline which has already been sufiiciently cracked. The object of the present invention is to prevent such gasoline from being. recracked by providing simple and so eli'ective method of stripping the gasoline out of the reflux condensate without in any way otherwise interfering with the normal operation of the process The invention will be understood from the fifiiollowing description, reference being bad to the accompanying drawing, in which the single figure is a more or less diagrammatic showing of an apparatus suitable for carryin out the invention. a

eferring to the drawing, 1 deslgnates a furnace in which is mounted a heating coil 2, oil is delivered-to the inlet side of the coil through feed line 3, and raw oil pump 4 connected to' any suitable source or" supply as,

for example, gas oil, fuel oil, or heavy crudes.

The oil is delivered from the coil, to transfer line 5 provided with throttle valve 6. The oil canpass directlythrough branch 7 controlled by throttle valve 8 to the expansion chamber 9, which expansion chamber may be insulated or independently heated, It is provided with a liquid draw-0d pipe 10, controlled by throttle valve 11 and-suitable mam holes (not shown} Vapors may pass out of the upper end or the expansion chamber 9 through vapor pipe 12 provided with throttle valve 13 into the lower side of a dephlegmator Vapors pass out of the top of the dephlegrnator through pipe 15 controlled by throttle valve 16 to condenser it, thence to receiver 18. This receiver 18 is provided with gas outlet pipe 19, controlled by throttle valve 20, and liquid drawofi pipe 21, controlled by throttle valve 22.

The reflux condensate is drawn out of the bottom of the dephlegmator through pipe 23, in which pipe 23 is interposed a hot oil pump 24, the pipe 23 connecting to the feed line 3. More or less of the reflux can be bypassed, if desired, through branch 25 by suitably controlling the valves 26, 27 and 28.,

As a feature of the invention, all or part of the hot oil from the transfer line 5 can be temporarily diverted from the expansion chamber 9 by means of the branch pipe 29 to closed coil 30 mounted in the lower part of the dephlegmator and returned to the expansion chamber 9 through pipe 31. Pipes 29 and 31 are provided with throttle valves 32 and 33 respectively, The arrangement is such that all or part of the hot oil may be initially passed through the closed coil 30 before it enters the expansion chamber. This results in keeping the lower part of the dephlegmator hot, with the result that as the ascending vapors meet the downwardly falling condensate, they are hot enough to insure the vaporization of substantially all of the gasoline dissolved in the reflux condensate. The desirability of keeping the lower part of the. dephlegmator hot in the manner shown in all the more accentuated if part of the raw charging stock is fed first to the dephlegmator and mixed with the reflux condensate, say by passing it up through pipe 35 controlled by valve 36. By suitably regulating valve 36 and valve 37 in the line 3, all or part-of the raw charging stock may be fed directly to the dephlegmator.

in certain types of oil where the reflux condensate and raw charging stock are mixed in the dephlegmator before passing to the tubes, as much as 5 to 12 per cent of gasoline is dissolved or contained in the mixture passing into the pipe 23. This results not only in unnecessarily subjecting the already suficiently cracked material to further araching, but of course results unnecessarily heating up already sut iciently cracked reaterial, 'lhe result of unnecessarily recraelr a ing such gasoline not only tends to injure the gasoline, but is wasteful of heat and cuts down the cracking capacity of the plant.

' sired, be maintained in the dephlegmator and the balance of the system. It will be seen from the foregoing description that the hot oil passing through the closed coil 30 tends to vaporize any gasoline contained in the descending condensate. Of course, care should be taken not to lower the temperature of the oil too much as it passes through the coil 30, and for this reason it probably will be only necessary in most cases to pass a portion of the oil through the coil 30, the balancev being passed directly through line 7 to the expansion chamber.

Temperatures and ressures may be used which will most satis actorily carry out the process, and I do not wish to limit myselfto temperatures and pressures shown, as either may vary several hundred degrees or several hundred pounds.

I claim as my invention:

1. An improvement in a continuous oil cracking process in which the oil is heated to a cracking temperature while passing through a heating coil, thence delivered to an enlarged zone wherein vaporization occurs and from which vapors pass to a reflux condenser, comprising delivering a portion of the oil which is passed through the heating coil directly to the enlarged zone, while passing a second portion of the oil, subsequent to its passage through the heating coil and prior to its introduction to the enlarged zone, through a portion of the reflux condenser, in heat interchange relation, but out of contact, with reflux condensate separated from the vapors in the reflux condenser, to effect a vaporization of gasoline-like con stituents from the reflux condensate, and

thereafter introducing said second portion of the oil to said enlarged zone.

- 2. In a hydrocarbon oil cracking process of the character wherein the oil is heated to cracking temperature while passing thru a heating coil, the heated oilthence discharged into an enlarged zone wherein vaporization occurs, and the vapors dephlegmated in a dephle mating zone to condense insufficiently cracke fractions thereof as reflux condensate; the improvement which comprises removing from the coil two separate streams treatment therein.

GUSTAV EGLOFF. 

